Coating apparatus



Sept. 2, 1941. A. B. PETERSON COATING APPARATUS Filed April 28, 1938 2 Sheets-Sheet l ANDREW B. PETERSON i Sill-Mini. i

Sept. 2, 1941. A. B. PE TERSON COATING APPARATUS Filed April 2a, 1938 2 Sheets-Shet 2 VE UZ"' ANDREW & PETER-SON Patented Sept. 2, 1941 2,254,391 COATING APPARATUS Andrew B. Peterson, Hoquiam, Wash., assignor to HarbonPlywood Corporation, Hoquiam, Wash., a corporation of Delaware Application April 28, 1938, Serial No. 204,758

3 Claims.

This invention relates to apparatus for coating sheet or slab material and more specifically relates to apparatus for glue coating wood veneers to form cores for plywood.

In the manufacture of weatherproof plywood for outdoor use, thermo-setting binders are used to permanently unite the constituent plies of a panel. It has been found that best gluing results are obtained when a thin, aqueous solution of a thermo-setting binder is first applied to the core sheet or veneer for penetration into the wood to a desired depth. This coating is dried under controlled conditions and the thus coated core sheet or veneer then receives a heavier coating of the thermo-setting binder thereon. The heavier coating remains on the surfaces of the core andis dried under controlled conditions.

According to this invention there is now provided apparatus for the coating of core sheets and veneers. The apparatus of this invention can be operated by one person feeding the uncoated cores into one end of. the device.

The machine of this invention includes a first roller coating device, a first drying device, a second roller coating device, and a second drying device arranged in tandem relationship with a single drive means controlling the operation of the entire apparatus.

The coating machines are especially adapted for the application of thin films over both broad faces of a Wood veneer sheet. The machines can be adjusted to apply an even film of any desired thickness over such broad faces of the wood veneers.

The drying apparatus following each coating machine include heating means and air circulation devices for drying the coating on the wood veneers at a rate and to a degree found desirable.

Interconnected conveyors carry the veneer sheets through the coating machines and the driers. The sheets automatically pass from one conveyor to another without manual aid so that an operator need only feed the sheets into the inlet end of the first coating machine.

It is then an object of this invention to provide a labor-saving coating apparatus.

Another object of this invention is to provide a device for the coating of sheet or slab material.

A further object of this invention is to provide a coating apparatus capable of being operated by one person.

Another object of this invention is to provide a machine for automatically coating core sheets for plywood.

Other and further objects of this invention will 55 vbecome apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings which disclose a preferred embodiment of the invention.

On the drawings:

Figure 1 is a somewhat diagrammatic side elevational View of a tandem coating and drying apparatus including coating machines of this invention.

Figure 2 is an enlarged horizontal cross-sectional view taken along the line 11-11 of Figure 1. Figure 3 is an enlarged vertical cross-sectional View taken along the line III-III of Figure 1. Figure 4 is an enlarged vertical cross-sectional view taken along the line IVIV of Figure l.

Figure 5 is an enlarged side elevational 'view of the first coating device shown in Figure 1.

Figure 6 is a top plan view. of the device shown in Figure 5. g

As shown on the drawings:

In Figure 1 the reference numeral [0 designates'generally the first coating machine receiv ing the uncoated veneer sheet for applying the initial coating to the broad faces thereof. The reference .numeral II designates generally the first drying apparatus receiving the veneer sheet from the coating machine II].

A second coating machine l2 receives the coated veneer sheets as the same are discharged from the drier II. The veneer sheets pass from the coating machine l2 into the second drier I3.

The passage of the veneer sheets through the entire machine is accomplished by a series of cooperating conveyors driven preferably from a single motor. I i v As shown in Figure l a veneer sheet V is fed to the first coating machine Ill by means of a conveyor M. The conveyor l4 feeds the veneer V between the coating rolls l5 and I6 of the machine [0. After passage between the rolls I5 and I6, the veneer sheet V is conveyed on a second (conveyor ll between conveyors l8 and I9 that extend through the open ended tunnel 20 of the drier ll.

The tunnel 20 is heated by means of steam pipes.2l located beneath the upper run of the conveyor I9 and'additional steam pipes 22 located above the lower run of the conveyor 18.

Air is circulated around the sheet V in the tunnel 20 by means of a fan and duct system including a fan 23 blowing air through a duct 24 and heater 25 into an inlet manifold 26 located at the discharge end of the tunnel 20.

The inlet manifold 26 as best shown in Figures 2 and 3 has a bifurcated end including a passageway 21 extending across the interior of the tunnel at the top thereof and a second passageway 28 extending across the interior of the tunnel along the bottom thereof. These passageways 21 and 28 open across the entire width of the tunnel toward the work inlet end of the tunnel.

As best shown in Figure 2, each passageway such as the passageway 21 has a plurality of baffles 29 and 33 therein defining sub-passageways therebetween for directing the air from the inlet 23 uniformly across the width of the tunnel.

Air is thus blown into the'tunnel at the work discharge end thereof and directed toward the work inlet end to circulate around the veneer sheets passing through the tunnel without interfering with the passage of the sheet.

The air is discharged through an outlet manifold 3| (Figures 1 and 4) located at the work inlet end of the tunnel 23'.

The outlet 3| likewise has a bifurcated end portion located within the tunnel and defining passageways 32 and 33 above and below the conveyors l8 and I9 respectively as best shown in Figure 4. These passageways 32 and 33 open toward the inlet passageways 21 and 28 but have closed back walls so that the air received therein is directed into the outlet 3|.

The outlet 3| communicates with the inlet end of the fan 23. A vent or stack 34 is provided in ,the duct 24 for bleeding moist air out of the system. A damper 35 in the duct 24 can be manually adjusted to control the amount of air bled out of the system. Fresh air is introduced through the open discharge end of the tunnel 20.

Upon leaving the heating tunnel ,23, the conveyors l8 and I8 deposit the veneer sheets V onto a conveyor 33. The conveyor 33 feeds the ribs 51 prevent the veneer sheets from sliding veneer sheets between the coating rolls 31 and 38 of the second coating machine l2. The thus coated veneer sheets are then conveyed on a conveyor 39 between a pair ofconveyors 40 and 4| extending longitudinally through the heating tunnel 42 of the second drier |3.

Heating coils 43 and along the top and bottom of the heating tunnel 42. These heating coils 43 and 44 preferably only extend about two-thirds of the length of the tunnel 42 from the work inlet end thereof.

Air is circulated over around the work passing through the tunnel by means of a fan and duct system including a fan 45 supplying air to an inlet 43 substantially identical with the inlet 23 of the tunnel 20. Air is removed from the tunnel through an outlet 41 having a bifurcated end similar to the end of the outlet 3| of the tunnel 23. Air is discharged from the outlet 41 into a duct 48 having a vent or stack 49 therein adapted to bleed air from the system. A damper 53 controls the amount of bleeding of air.

The exit one-third of the heating tunnel has air circulated therethrough from the work discharge end thereof by means of a fan 5| that draws air through an outlet duct 52 and discharges the air into a duct or stack 53.

In the drier l3, therefore, the second coating 'on the veneer sheets V is dried in an atmosphere heated by heating coils 43 and 44. The-tunnel 42.is of suflicient length so that the coatings will be dried before the same reach the discharge end of the tunnel. This makes possible a cooling of the veneer sheets before the same are discharged from the drier by means of unheated air drawn into the work discharge end of the tunnel.

44 extend longitudinally the heating coils and As best shown in Figures 2 to 4 inclusive, all of the conveyors |4, |1, |3, I3, 33, 33, 43 and 4| comprise spaced parallel tracks 55 of a somewhat U -shape as shown in Figures 3 and 4. Chains'53 slide on their upper runs along tracks 55. Transverse ribs 51 are secured to the chains 53 at spaced parallel intervals. The ribs 51 carry the veneer sheets thereon.

The lower runs of the conveyors l8 and 48 extending through the tunnels 23 and 42 respectively sag downward so that their ribs 51 rest on top of the veneer sheets supported by the ribs 51 of the lower conveyors I9 and 4|. These top and also hold the same against warping and buckling during the drying operation.

The coating machines l0 and I2 are identical. Therefore the first coating machine |3 need only be described. The machine ID, as shown in Figures 5 and 6, includes a frame 30. Spaced vertical side plates 3| are mounted on the frame 33 at the front and back sides thereof. Side plates. 32 are mounted on top of the plates 3| and are pivoted thereto as at 33.

Each plate 3| has a bracket 34 secured to the end thereof. The brackets 34 extend above the tops of the plates 3| and 32 and have slots 34a formed therein for receiving in slidable relation thereto the ends of nuts such as 32a projecting from the pivotally mounted plates 32. The free ends of the plates 32 are thus guided in the slots 34a of the brackets 34. 7

Each bracket 34 has a boss portion 35 formed at the top thereof above the plate 32. Shafts 33 are rotatably mounted in the bosses 35 of the brackets. The bottom ends of the shafts 33 are threaded into bosses 31 carried on the plates 32.

The shaft 33 at the front side of the machine receives a hand wheel 38 at the top end thereof. A sprocket gear is keyed to the shaft 33 below the hand wheel 38. A second sprocket gear 13 is keyed to the top of the shaft at the rear side of the machine. An endless chain 1| is trained around the gears 33 and 13 and therewith so that a rotation of the han wheel 38 will effect rotation of both shafts 33 into and out of their respective bosses 31 on the side plates 32 for raising and lowering the side plates.

The bottom coating 'roll l3 extends transversely-between the plates 3| and has the axles |3a thereof rotatably mounted in bearing blocks fixedly carried by the plates.

A feed roll 12 also extends transversely between the plates 3| alongside of the coating roll l3 and has the axles 12athereof rotatably mounted in bearing blocks 13 slidably carried on the sides of the plates 3|. The bearingblocks 13 are adapted to be moved relatively to the plates 3| by means of adjusting nuts 14 carried on the outer sides of the plates. This arrangement provides for the movement of the feed roll 12 toward and away from the lower coating roll l3.

The upper coating roll I5 extends transversely between the upper plates 32 and has the axles |5a thereof rotatably mounted in bearing blocks 15 fixedly carried by the plates 32.

A feed roll 13 extends alongside of the roll I5 between the plates 32 and has the axles 13a thereof mounted in slidable bearing. blocks 11 .carried by'the plates 32 in the same manner in eshes The hopper drains into a pipe 8| feeding a pump 82. The pump 82 forces glue solution upward through a pipe 83 having a T coupling 84 at the end thereo. A vertical pipe 85'is.secured in the bottom-opening of the T 84 and is positioned directly over the nip between the feed roll I6 and the top coating roll I5. A pipe line 81 is also secured in the T 84 and extends into the nip between the lower feed roll I3 and lower coating roll I6.

The hopper 80 can be charged with a supply of binder solution. When the pump 82 is in operation this solution will be discharged out of the pipes 85 and 81 into the nips between the coating rolls and their respective feed rolls.

Pressure between the coating rolls and their feed rolls can be regulated by sliding the feeding rolls toward and away from the coating rolls by means of the adjusting bolts such as I4. In this manner the film thickness of glue or binder solution carried on the coating rolls can be regulated.

The pressure between the coating rolls I and I6 can be controlled by raising and lowering the free ends of the top plate 62. This is accomplished by rotation of the hand wheel 68. Since.

both shafts 66 are operated in unison the top roll I5 will not be cooked and will bear against the bottom roll I6 with the same pressure across the entire length of the nip between the rolls.

As best shown in Figures 5 and 6,-the chains of the conveyor I4 are trained around pairs of sprocket gears 90 and 9|. The sprocket gears 90 are carried on a shaft 92 mounted between brackets 94 carried on the main frame. The sprocket gears 9| are carried on a shaft 93 mounted between brackets 95 carried on the main frame.

The front end of the shaft 93 has a'sprocket gear SB'thereon receiving a drive chain 91 therearound. The other end of the drive chain 91 is trained around a sprocket gear 98 secured on an extension of the axle Ilia of the bottom coating roll I6. This same extension of the axle, as best shown in Figure 5, has a second sprocket gear 99 secured thereon driven by a drive chain I00. The drive chain I00 is trained around a sprocket IOI carried by a shaft I02 supporting sprocket gears I03 around which the chains of the conveyor I9 are trained.

The conveyor I! has the chains thereof trained around sprockets I04 and I05 carried on shafts I06 and I01. The shaft I0! is supported in brackets I08 carried on the main frame of the machine and is driven at the rear end thereof by a motor I09. A chain. 0 and sprocket III operatively join the shafts I01 and I02 so that a rotation of the shaft I0! by the motor- I09 also causes a rotation of the shaft I02 to drive the lower conveyor I9. The rotation of the shaft I02 drives the sprocket gear IOI for driving the chain I00. The chain I00 drives the sprocket gear 99 and rotates the coating roll I6.

At the same time the sprocket gear.98 is driven,

to drive the chain 9'! which in turn drives the conveyor I I.

Rotation of the lower coating roll I6 drives the upper coating roll I5. This upper coating roll in turn drives the chain 3 operatively connected with sprockets II4 around which the upper conveyor chain I8 is mounted. This causes a driving of the upper conveyor. The work discharge end of the lower conveyor I9 is operatively connected through a chain II5 to the conveyor 36 of the second coating machine I2. This second coating machine I2 is machine I0.

With this system it is obvious that the single motor I09 can drive all of the conveyors so that the veneer sheets need only be fed onto the conveyors I4 for automatic passagethroughout the entire apparatus.

From the above descriptions it should be understood that the invention comprises an apparatus for handling sheets or slabs to apply a plurality of coatings to the broad faces thereof and to dry each coating after its application onto the sheets or slabs. The coating machines of the invention can be nicely adjusted to supply glue or other coating material in any desired amount to the sheets or slabs. The coatings are applied in uniform, even films and the feed rolls or doctor rolls cooperating with the coating rolls make possible the use of corrugated soft rubber coating rolls since they will not damage such soft rolls as will the usual doctor bar. The use of doctor rolls or feed rolls in place of doctor bars also makes possible the maintenance of any desired amount of pressure against the coating rolls 1 carried thereby, a doctor roll extending betweensaid plates alongside of said coating roll, bearing blocks carried by said plates rotatably supporting the doctor roll, means for sliding the bearing blocks relative to the plates to move the doctor roll toward and away from the coating roll, additional plates mounted on top of said plates and pivotally connected thereto. a top coating roll rotatably mounted between said additional plates above said first mentioned coating roll, a doctor roll for said top coating roll also mounted between said additional plates, and means for swinging the top plates about their pivot points for regulating the pressure between the coating rolls. I

2. A coating machine comprising a pair of spaced vertical side plates, means for fixedly mounting said side plates, top plates on topof said side plates, means pivotally connecting one end of 'said top plates with the fixedly mounted plates, coating rolls extending transversely'between said plates in superimposed relation, the

- lower of said coating rolls being rotatably mountmounted plates, and means for swinging said pivotally mounted plates about their pivot points to adjust the pressure between the coating rolls.

3. In a coating machine including a pair of spaced vertical side plates, means for fixedly mounting said'side plates, paired superimposed coating rolls, the lower of said coating rolls being rotatably carried by said side plates, doctor rolls for said coating rolls, the doctor roll for said iower coating rollbeing rotatahly carried by said side plates, and means for adjusting the position ofthe doctor rolls relative to the coating rolls, the improvement comprising top plates on top of said side plates rotatabiy supporting said upper coating 'roll and doctor roll, means pivotally connecting one end of each top plate with 

